CP TD1 Reference Manual V 1.44
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12.9.3 Fault Localization
In order to find out the reason for high gas values, further tests have to be
performed for the transformer. Common test methods are:
• Winding resistance measurement
• On-Load Tap Changer (OLTC) test
• Turns ratio measurement
• Excitation current measurement
• Measurement of leakage reactance
• Capacitance and Dissipation factor measurement
Figure 12-8 A multi-functional transformer test and diagnosis system
In this paper, all tests were performed with a new self-contained test system.
The device comprises a Digital Signal Processor (DSP) which generates
sinusoidal signals in a frequency range of 15 to 400 Hz which is fed into a
switched-mode power amplifier. A transformer at the output matches the internal
amplifier impedance with the test object impedance [8]. By utilizing test
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